The State Department has had a policy in place since 2005 to warn officials against routine use of personal e-mail accounts for government work, a regulation in force during Hillary Clinton’s tenure as secretary of state that appears to be at odds with her reliance on a private email for agency business, POLITICO has learned.

The policy, detailed in a manual for agency employees, adds clarity to an issue at the center of a growing controversy over Clinton’s reliance on a private email account. Aides to Clinton, as well as State Department officials, have suggested that she did nothing inappropriate because of fuzzy guidelines and lack of specific rules on when and how official documents had to be preserved during her years as secretary.

But the 2005 policy was described as one of several “clear cut” directives the agency’s own inspector general relied on to criticize the conduct of a U.S. ambassador who in 2012 was faulted for using email outside of the department’s official system.

“It is the Department’s general policy that normal day-to-day operations be conducted on an authorized [Automated Information System], which has the proper level of security control to provide nonrepudiation, authentication and encryption, to ensure confidentiality, integrity, and availability of the resident information,” the Department’s Foreign Affairs Manual states.

Spokespeople for the State Department and Clinton stressed earlier this week that the agency had “no prohibition” on the use of private e-mail for work purposes.

Clinton said in a tweet Wednesday night that she wants the public to be able to see the emails she has turned over to the State Department in December. But the agency said that a review process that includes seeing if the documents contain personal or classified information could take some time to complete.

The 2005 policy says approved “telework solutions” satisfy the rule, which appears in a section of State Department regulations discussing “sensitive but unclassified” information — an extremely broad category of data. Former officials said a large volume of State Department paperwork and e-mail falls into the category known internally as “SBU.”

The email policy gained some attention when the inspector general issued a scathing report on the tenure of retired Air Force Maj. Gen. Scott Gration as U.S. ambassador to Kenya. The review, which led to his resignation three years ago, faulted him on a variety of grounds: one was having “a commercial Internet connection installed in his embassy office bathroom so he could work there on a laptop not connected to the Department email system.”

Another complaint the report leveled against Gration: “He drafted and distributed a mission policy authorizing himself and other mission personnel to use commercial email for daily communication of official government business.”

A State official who asked not to be named noted that the email issue was just one of a series of serious management shortcomings described in the 2012 inspector general report about U.S. Embassy operations in Kenya.

State Department officials and Clinton aides have offered no response to questions in recent days about how her private e-mail system was set up, what security measures it used, and whether anyone at the agency approved the arrangement. It’s unclear how such a system, run off an internet domain apparently purchased by the Clinton family, could have won approval if the department’s policies were as the inspector general’s report describes them.

Clinton sent 55,000 pages of e-mails from her private account to the State Department in December, after State officials asked Clinton and other former secretaries to provide copies of any work-related e-mail messages so they could be incorporated into the agency’s official record systems.

The former secretary said on Twitter Wednesday, “I want the public to see my email. I asked State to release them. They said they will review them for release as soon as possible,” Clinton tweeted.

Chelsea Clinton also had an account on the homemade website domain that Hillary Clinton used exclusively for emails during her time as secretary of state, The New York Times reports. The domain name had a server linked to the family’s Chappaqua, New York, residence. But her real name is absent from the email address.

She used her clintonemail.com account under the pseudonym “Diane Reynolds,” which the Times reports she often used when checking into hotels.

Longtime Clinton aide Huma Abedin also had a clintonemail.com account, according to the report, an apparent prized symbol of status within Clinton’s vast network of advisers, well-wishers, and hangers-on.

According to Philippe Reines, another close Clinton aide and former State Department official, Abedin was the only department official other than the secretary to use a clintonemail.com account.

Clinton tweeted late Wednesday that she wants the public to see emails from the 55,000 pages she handed over to the State Department.